The field of the invention generally relates to refrigerators, and more particularly relates to air flow control apparatus for providing independent control of a multi-port refrigerator duct.
As is well known, a foam-in-place process is commonly used to manufacture domestic refrigerators. In such process, a plastic liner is positioned in a metal shell or cabinet. Then, foam insulation under pressure is injected into the space between the liner and the shell, and the foam flows along the bottom, sides, and top of the liner thereby filling the voids in the space. Subsequently, the foam solidifies and becomes rigid insulation.
In the case of a side-by-side refrigerator, a freezer liner is generally positioned on one side and a fresh food liner is positioned on the opposite side. The two respective liners are spaced so that the foam flows into the region therebetween forming a vertical partition. Typically, an evaporator chamber is formed within the freezer liner, and a single fan is used to circulate air from the freezer and fresh food compartments over the evaporator and back to the respective compartments. The evaporator is activated and the air proportioned so that the freezer compartment is generally maintained at a approximately 0.degree. F. while the fresh food compartment is approximately 40.degree. F. It is also well known that it is desirable to maintain certain foods at an intermediate temperature such as in the range from 32.degree. F.-35.degree. F. For example, meat is commonly stored in a meat keeper drawer within the fresh food compartment, and beverages or foods requiring quick chill are stored temporarily or permanently in a storage compartment typically located in the fresh food door. One important design consideration involves how to convey cold air from the freezer through the partition of foamed-in-place insulation to the storage chambers in the fresh food liner.
U.S. Pat. No. 4,586,347 discloses a side-by-side refrigerator having an intermediate temperature chamber within the fresh food door. A port or passage is provided directly through the vertical partition between freezer and fresh food compartments, and the respective pressures are maintained so that cold air flows from the freezer compartment laterally through the passage in the partition to the storage chamber. However, with a wide range of freezer and fresh food compartment operating conditions such as the size and quantity of stored food, the pressures in the respective compartments may tend to be variable. Therefore, one problem with such arrangement is that it may be difficult to regulate or control the temperature within the storage chamber. Further, there may be additional cold air conveying apparatus required for a meat keeper storage chamber and, if the apparatus is the same as for the door chamber, it may be difficult to provide independent temperature control. That is, by adjusting the temperature setting of the meat keeper or door storage chamber, the temperature of the other may be affected.